Odd Period Square Roots (64)

In Problem 64, we're asked to look at the continued fractions of the square roots of natural numbers N$N and investigate their the periodic part of the expansion. Specifically, we are asked how many expansion of $\sqrt{N}$ for $N\le 10000$ have an odd period.

With the library for continued fractions, we can directly get the prefix and period part for every $N$. We just check for odd length and count these.